<!doctype html>
<html lang="zh">

<head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, user-scalable=no">
    <style>
        html,
        body {
            margin: 0;
            padding: 0;
            background-color: #f8f9fa;
        }

        .container {
            min-height: 100vh;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 60px;
            font-weight: bold;
            font-family: 'Courier New', Courier, monospace;
        }

        .cursor {
            animation: cursor .3s infinite;
        }

        @keyframes cursor {

            0%,
            100% {
                opacity: 0;
            }

            50% {
                opacity: 1;
            }
        }
    </style>
</head>

<body>

    <!--该页面请无视，只是静态html托管平台需要的错误页面而已-->
    <div class="container">
        <span class="status">4 0 4</span>
        <span class="cursor">|</span>
    </div>

    <script>
        function sleep(duration) {
            return new Promise(resolve => setTimeout(resolve, duration));
        }

        async function updateMsgBox() {
            const msgBox = document.querySelector('.status');
            while (true) {
                await sleep(3000);
                msgBox.innerHTML = '';
                await sleep(700);
                msgBox.innerHTML = '4';
                await sleep(700);
                msgBox.innerHTML = '4 0';
                await sleep(700);
                msgBox.innerHTML = '4 0 4';
            }
        }

        updateMsgBox();
    </script>
</body>

</html>